WARSAW, Poland (AP) —

Poland has received its first shipment of U.S.-made HIMARS rocket launchers, part of an upgrade of its defenses amid security concerns due to the war in neighboring Ukraine.

Defense Minister Mariusz Blaszczak and other military officials attended the acquisition ceremony Monday at an air base in Warsaw.

He stressed the HIMARS launchers had been proven in combat in Ukraine and that NATO member Poland was seeking to procure additional launchers, to reach a total strength of some 500 units.

Under a 2019 contract, Poland is spending some $414 million (380 million euros) to buy 18 advanced combat HIMARS launchers and two HIMARS training launchers, with ammunition and related equipment. Poland is buying billions of dollars' worth of weapons, chiefly from the U.S. and South Korea, to modernize its armed forces. The deal includes logistics and training.

Some of the equipment will replace weapons - including over a dozen Soviet-made MiG-29 jet fighters - that Poland has been handing to Ukraine to help it fight Russia’s invasion of almost 15 months.

The M142 HIMARS, or High Mobility Artillery Rocket System, is a multiple rocket launcher with a range of up to some 300 kilometers (190 miles) developed in the late 1990s for the U.S. armed forces.

Poland's right-wing government, which will be seeking a third term in parliamentary elections in the fall, is giving the purchases wide publicity, seeking to reassure Poles amid a military conflict across their eastern border.

Last year, Poland received a number of U.S. Patriot missile systems, and deliveries of another battery are expected this year. The first deliveries of Abrams tanks have also arrived from the U.S., as well as deliveries of tanks and howitzers from South Korea.

Poland is also purchasing U.S. F-35 and South Korean FA-50 jet fighters.